Aircraft avionics systems include automatic flight controls and other systems to aid the pilot in navigation of the aircraft. Typically, a primary flight display (PFD) provides the pilot an indication of the current modes of operation of the aircraft. For example, above the altitude scale on the PFD a normally static alphabetic representation is given of one or more of the vertical navigational mode, the speed or throttle mode and the lateral navigational mode for the aircraft. These representations are frequently referred to as mode annunciation. Examples of vertical navigational modes of operation include altitude hold (ALT), altitude select (ALTS), glideslope (GLS), and vertical navigation (VNAV). Examples of lateral navigational modes of operation include flight management system (FMS), VHF omnidirection radio (VOR), localizer (LOC), distance measuring equipment (DME), microwave landing system (MLS), and global positioning system (GPS) modes. Examples of throttle modes include speed (SPD) and time navigation (TNAV).
A fundamental problem facing pilots is maintaining situational awareness of the aircraft and knowing what actions the automatic flight control system will require next. In conventional flight control systems, changes in operational modes or other events such as passing over a marker beacon have been annunciated by causing some text to flash for a few second beginning at the appropriate moment. Prior to occurrence of the event and the resulting flashing of the text, awareness that the event is upcoming is difficult since all the pilot sees is a static text annunciation. Lack of situational awareness can be a particular problem in controlled flight into terrain, thus causing the pilot to miss the airport by a significant distance.
Consequently, an avionics display which overcomes these and other problems by providing the pilot with improved situational awareness of upcoming events and modes of operation would be a significant improvement in the art.